| Structural highlights
6cci is a 1 chain structure with sequence from Arath. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | CA, CO, NAG |
| Gene: | ESK1, TBL29, At3g55990, F27K19.170 (ARATH) |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[TBL29_ARATH] Probable xylan acetyltransferase required for 2-O- and 3-O-monoacetylation of xylosyl residues in xylan. Negative regulator of cold acclimation. Involved in water economy as well as salt tolerance. Regulated at the transcriptional level by NAC012/SND1 (PubMed:17316173, PubMed:19054354, PubMed:19061521, PubMed:21408051, PubMed:23340742, PubMed:23659919). May act as a bridging protein that binds pectin and other cell wall polysaccharides. Probably involved in maintaining esterification of pectins (By similarity).[UniProtKB:Q9FG35][1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
Xylans are a major component of plant cell walls. O-Acetyl moieties are the dominant backbone substituents of glucuronoxylan in dicots and play a major role in the polymer-polymer interactions that are crucial for wall architecture and normal plant development. Here, we describe the biochemical, structural, and mechanistic characterization of Arabidopsis (Arabidopsis thaliana) xylan O-acetyltransferase 1 (XOAT1), a member of the plant-specific Trichome Birefringence Like (TBL) family. Detailed characterization of XOAT1-catalyzed reactions by real-time NMR confirms that it exclusively catalyzes the 2-O-acetylation of xylan, followed by nonenzymatic acetyl migration to the O-3 position, resulting in products that are monoacetylated at both O-2 and O-3 positions. In addition, we report the crystal structure of the catalytic domain of XOAT1, which adopts a unique conformation that bears some similarities to the alpha/beta/alpha topology of members of the GDSL-like lipase/acylhydrolase family. Finally, we use a combination of biochemical analyses, mutagenesis, and molecular simulations to show that XOAT1 catalyzes xylan acetylation through formation of an acyl-enzyme intermediate, Ac-Ser-216, by a double displacement bi-bi mechanism involving a Ser-His-Asp catalytic triad and unconventionally uses an Arg residue in the formation of an oxyanion hole.
Molecular Mechanism of Polysaccharide Acetylation by the Arabidopsis Xylan O-acetyltransferase XOAT1.,Lunin VV, Wang HT, Bharadwaj VS, Alahuhta M, Pena MJ, Yang JY, Archer-Hartmann SA, Azadi P, Himmel ME, Moremen KW, York WS, Bomble YJ, Urbanowicz BR Plant Cell. 2020 Jul;32(7):2367-2382. doi: 10.1105/tpc.20.00028. Epub 2020 Apr, 30. PMID:32354790[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Xin Z, Mandaokar A, Chen J, Last RL, Browse J. Arabidopsis ESK1 encodes a novel regulator of freezing tolerance. Plant J. 2007 Mar;49(5):786-99. doi: 10.1111/j.1365-313X.2006.02994.x. PMID:17316173 doi:https://dx.doi.org/10.1111/j.1365-313X.2006.02994.x
- ↑ Lugan R, Niogret MF, Kervazo L, Larher FR, Kopka J, Bouchereau A. Metabolome and water status phenotyping of Arabidopsis under abiotic stress cues reveals new insight into ESK1 function. Plant Cell Environ. 2009 Feb;32(2):95-108. doi: 10.1111/j.1365-3040.2008.01898.x., Epub 2008 Nov 20. PMID:19054354 doi:https://dx.doi.org/10.1111/j.1365-3040.2008.01898.x
- ↑ Bouchabke-Coussa O, Quashie ML, Seoane-Redondo J, Fortabat MN, Gery C, Yu A, Linderme D, Trouverie J, Granier F, Teoule E, Durand-Tardif M. ESKIMO1 is a key gene involved in water economy as well as cold acclimation and salt tolerance. BMC Plant Biol. 2008 Dec 7;8:125. doi: 10.1186/1471-2229-8-125. PMID:19061521 doi:https://dx.doi.org/10.1186/1471-2229-8-125
- ↑ Lefebvre V, Fortabat MN, Ducamp A, North HM, Maia-Grondard A, Trouverie J, Boursiac Y, Mouille G, Durand-Tardif M. ESKIMO1 disruption in Arabidopsis alters vascular tissue and impairs water transport. PLoS One. 2011 Feb 1;6(2):e16645. doi: 10.1371/journal.pone.0016645. PMID:21408051 doi:https://dx.doi.org/10.1371/journal.pone.0016645
- ↑ Xiong G, Cheng K, Pauly M. Xylan O-acetylation impacts xylem development and enzymatic recalcitrance as indicated by the Arabidopsis mutant tbl29. Mol Plant. 2013 Jul;6(4):1373-5. doi: 10.1093/mp/sst014. Epub 2013 Jan 22. PMID:23340742 doi:https://dx.doi.org/10.1093/mp/sst014
- ↑ Yuan Y, Teng Q, Zhong R, Ye ZH. The Arabidopsis DUF231 domain-containing protein ESK1 mediates 2-O- and 3-O-acetylation of xylosyl residues in xylan. Plant Cell Physiol. 2013 Jul;54(7):1186-99. doi: 10.1093/pcp/pct070. Epub 2013, May 9. PMID:23659919 doi:https://dx.doi.org/10.1093/pcp/pct070
- ↑ Lunin VV, Wang HT, Bharadwaj VS, Alahuhta M, Pena MJ, Yang JY, Archer-Hartmann SA, Azadi P, Himmel ME, Moremen KW, York WS, Bomble YJ, Urbanowicz BR. Molecular Mechanism of Polysaccharide Acetylation by the Arabidopsis Xylan O-acetyltransferase XOAT1. Plant Cell. 2020 Jul;32(7):2367-2382. doi: 10.1105/tpc.20.00028. Epub 2020 Apr, 30. PMID:32354790 doi:https://dx.doi.org/10.1105/tpc.20.00028
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